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BRD7是采用cDNA代表性差异分析法克隆的一个新的Bromodomain基因,过表达BRD7可抑制鼻咽癌细胞的生长和细胞周期进程,同时发现BRD7基因可以调控Rb/E2F通路的活性.该研究旨在进一步探讨BRD7调控Rb/E2F通路的分子机制.通过蛋白质印迹和RT-PCR实验方法发现,BRD7能够降低Rb的磷酸化水平,抑制cyclinD1、cyclinE的蛋白质表达,上调CDK4抑制子P19的mRNA表达,但对CDK4和CDK2的蛋白质表达没有明显影响;通过荧光素酶实验从转录调控水平进一步证实了BRD7能够明显抑制cyclinD1启动子活性;采用反义核酸技术抑制COS7细胞内源性BRD7的表达后,发现cyclinD1、cyclinE、磷酸化Rb的蛋白质表达水平上调,并且可以促进细胞生长.这些结果表明:BRD7参与调控Rb/E2F信号通路中重要靶分子的表达,抑制Rb/E2F通路的活性,从而阻止细胞周期G1-S期进程,抑制鼻咽癌细胞生长.
BRD7 is a new Bromodomain gene cloned by cDNA representative differential analysis. Overexpression of BRD7 can inhibit the growth and cell cycle progression of NPC cells, and found that BRD7 gene can regulate the activity of Rb / E2F pathway.The aim of this study The molecular mechanism of BRD7 in regulating Rb / E2F pathway was further explored.The results of Western blot and RT-PCR indicated that BRD7 could reduce the phosphorylation of Rb, decrease the protein expression of cyclinD1 and cyclinE, and upregulate the expression of CD19 repressor P19 The expression of cyclinD1 was significantly inhibited by the luciferase assay, which further confirmed that BRD7 could inhibit the cyclinD1 promoter activity. The antisense oligonucleotide was used to inhibit the expression of endogenous BRD7 in COS7 cells. The results showed that cyclinD1 , CyclinE and phosphorylated Rb protein, and promote cell growth.These results indicate that BRD7 is involved in the regulation of the expression of important target molecules in the Rb / E2F signaling pathway and the inhibition of the activity of the Rb / E2F pathway, thereby preventing cell cycle G1 -S phase of the process, inhibition of nasopharyngeal carcinoma cell growth.